Patent GB-190619878-A (GB)
Title: Improvements in and relating to Apparatus for use in Signalling by Electro-magnetic Waves.
Filed: 1906-09-06
Granted: 1907-02-21
Abstract: 19,878. De Forest Wireless Telegraph Syndicate, [Forest, L. de]. Sept. 6. Bearings, instruments for determining.-Relates to apparatus for signalling by electro-magnetic waves, the' chief object being to enable a ship or other moving body provided with receiving-apparatus to locate its position with respect to a stationary or moving body provided with transmitting -apparatus. A prime-mover J, Fig. 1, drives a generator G by a belt K, and a signalling-wheel Q by a worm P and a worm-wheel P', the worm shaft being driven by belting from the prime-mover. A brush R makes electric contact with the wheel Q, and a brush R<1> makes connexion at intervals with contacts S with which the wheel is provided. The primary of a step-up transformer is included in the generator circuit, the secondary being connected to the spark-gap A<1> through brushes 7, 8 and rings 7<1>, 8<1>. A reflector B of parabolic or other suitable shape carries the oscillator by means of insulators g, g<1> and is rotated by shafts I, F and bevel-gearing. The operation of the prime-mover J causes the oscillator A to emit electro-magnetic waves, which are concentrated in one direction by the reflector B, this direction being continuously varied. For the purpose of transmitting direction-indicating signals, the wheel Q is divided into sixteen sectors as shown in Fig. 2, each being provided with contacts S, S', &c. and adapted to produce a series of one or more dots according to the position of the reflector. The wheel Q is also provided with frequently recurring contacts T, which are different for each transmitting device or "aero- "phore" in order to indicate the location of the aerophore from which the direction signals are transmitted. The action of a modified transmitting-device depends upon the fact that the radiation of the electro-magnetic waves from an inclined antenna is most intense in the direction of inclination. Fig. 5 shows a receiving-device adapted for use on board ships with an apparatus as shown in Fig. 1. Geared to a wheel 12<1> driven by the, motor J is a wheel 12 which intermittently moves the switch 5<x> by means of the rods 9, 10. When the generator circuit is closed, a contact 8 cooperates with contacts 7, thereby shunting the responder R and disconnecting the receiving-antenna at the point 6. When the generator circuit is broken, the circuit 5<x> is in such a position that the shunt round the responder R is broken at the contacts 7, and the antenna; are connected to earth through the responder at the point 6, so that a signal emitted by an aerophore on another ship may be received by responder R, thereby energizing the magnet T and closing the circuit of the indicator D. For trains and other vehicles which travel in a fixed direction, it is only necessary to concentrate the radiation in the direction of the track, for which purpose horizontal or slightly inclined antennµ are connected to the roof of the vehicle. A disk driven from the prime-mover has conducting and non-conducting sectors alternately on its periphery upon which brushes bear, so that the receiving and transmitting devices are alternately connected to the antennµ, a device similar to that shown in Fig. 5 protecting the receiver during transmission.